The main parameters of residential buildings are water supply, sewer system and delivery electrical energy. Regardless of the number of residents ( a private house or multi-storey), the calculation of the main networks must be carried out according to certain rules, using the appropriate formulas. It does not take much time to create the correct electrical circuit; it is much more difficult to decide on the water supply. A particular difficulty is the design and calculation of feed hot water. In order to carry out all operations correctly, you need to know not only the technical side of the issue, but also the regulatory framework.

The most commonly chosen type of network is the circulation type. The principle of operation of such a system is the constant circulation of liquid. The only disadvantage of a circulating hot water supply system is that it is too expensive. The costs are only justified when the maximum number of users for a residential building is reached.

Also, in addition to the high pricing policy, constant circulation of water leads to significant heat losses, which entails additional costs. If there is a circulation system, designers try to reduce the length of the pipeline as much as possible. This option allows for additional savings on liquid transportation.

What is the waiting period and how is it calculated?

The waiting period is the time period that passes from the time the user opens the tap until hot water is supplied. They try to reduce this time as much as possible; for this purpose, the hot water supply system is optimized, adjustments are made, and if the indicators are poor, they are modernized.

To set the waiting period, generally accepted standards are used. To calculate it correctly, you should know the following:

• To reduce the waiting period, you should create high pressure water in the system. But setting too high pressure parameters can damage the pipeline.
• To reduce the waiting period, increase throughput device through which the user receives liquid.
• The waiting period increases in direct proportion to the internal diameter of the pipeline, as well as if there is a circuit at a large distance from the consumer.

The correct sequence for calculating the waiting period is:

• Determination of the number of consumers. After the exact figure, you should make a small reserve, since there are peak hot water consumption.
• Determination of the characteristics of the pipeline: length, internal diameter of the pipes, as well as the material from which they are made.
• Multiplying the length of the pipeline and its internal diameter by the specific volume of water, which is measured in l/s.
• Determination of the shortest and most convenient fluid path. This parameter also includes sections of the circuit located farthest from the water tap. All volumes of water are also added.
• The amount of liquid is divided by the water flow per second. When obtaining this parameter, the total fluid pressure in the system is also taken into account.

To achieve the most accurate results, you should correctly calculate the specific volume of the pipeline. The following formula is used for this:

Cs = 10 (F/100)2 3.14/4, where F is the internal diameter of the pipeline.

When determining the specific volume, you cannot use the value of both the external and nominal diameter of the pipes. This will significantly reduce the accuracy of calculations. There are tables in which the specific volume value is pre-calculated for certain materials (copper and steel).

Calculation of hot water consumption per day

The amount of hot water that the user needs per day is a parameter calculated in advance. Typically, such data is taken from tables, where they are divided by type of room and its square footage. European parameters should not be confused with those of other countries; they are strikingly different from each other.

On average, hot water consumption per person per day ranges from 25 to 50 liters. Compiling and calculating the amount of hot water per person is possible only after the status of the room or building is known.

How to calculate a pipeline

For long-term operation of a hot liquid transportation system, the pipeline should be calculated under peak load conditions. This allows you to make a certain reserve, which will eliminate the occurrence of malfunctions in the system with a sharp increase in pressure.

To calculate a pipeline, most often, ready-made diagrams and tables with relevant data are used. The material most often used is copper or galvanized steel. You should know that an important calculation parameter is the equivalent Fixture Unit. This device called a conditional element for a certain type of water folding mechanisms.

Pipeline calculation sequence:

• The calculation begins with determining the Fixture Unit parameter, which is mandatory for each water intake point.
• The main hot water transportation network is divided into separate sections (nodes). The principle is based on the design of the heating system.
• Find the total number of Fixture Units that will be located at different sites.
• Based on the total Fixture Unit amount and the type of building, the estimated flow rate for each section of the system is found.
• Design flow, also referred to as throughput volume, is an important component in determining the diameter of the pipeline. The internal diameter of the pipes is determined under the condition that the final figures will not exceed generally established limits.

When calculating the circulation network, you can use general position, that for each Fixture Unit element there is 3 l/s. A separate point is the calculation re circulation pump, which has a certain throughput capacity. To determine this parameter, it is necessary to know the exact number of water points.

To provide the circulation network with additional savings, a thermostat is installed on the pump. The thermostat ensures that the device turns on when the temperature of the transported liquid drops. When the water temperature on the return circuit reaches a value less than the nominal value by 5 degrees, the pump turns off.

What you need to have to start calculating hot water supply

It is impossible to start calculating a hot water supply system without having technical and design documentation for the house. At the same time, the size of the house is not important; a private plot requires the same plan as a multi-story building.

The calculation begins with a certified architectural plan, on which the selected correct location buildings, as well as the placement of sanitary fixtures. The location of the house will help you choose the water supply system along the shortest route.

It is necessary to know the number of people who will live in the building. Naturally, it is impossible to find out the exact number of residents, so it is better to carry out the calculation using the maximum data. Such figures will allow you to calculate the correct time of peak loads.

Determine the location where the hot water supply equipment will be placed. This area, must be indicated on the diagram.

DHW calculations, BKN. We find the volume, power of the hot water supply, power of the BKN (snake), warm-up time, etc.

In this article we will consider practical problems for finding the volume of hot water accumulation and DHW heating power. Heating equipment power. Hot water readiness time for various equipment and the like.

Let's look at examples of tasks:

Task 1. Find power instantaneous water heater

Instantaneous water heater- This is a water heater, the volume of water in which can be so small that its existence is useless for storing water. Therefore, it is believed that an instantaneous water heater is not intended to accumulate hot water. And we do not take this into account in our calculations.

Given: Water consumption is 0.2 l/sec. Temperature cold water 15 degrees Celsius.

Find: The power of an instantaneous water heater, provided that it heats the water to 45 degrees.

Solution

Answer: The power of the instantaneous water heater will be 25120 W = 25 kW.

It is practically not advisable to consume a large number of electricity. Therefore, it is necessary to accumulate (accumulate hot water) and reduce the load on electrical wires.

Instantaneous water heaters have unstable heating of hot water. The hot water temperature will depend on the water flow through the instantaneous water heater. Power or temperature switching sensors do not allow for good temperature stabilization.

If you want to find the output temperature of an existing instantaneous water heater at a certain flow rate.

Task 2. Electric water heater (boiler) heating time

We have an electric water heater with a capacity of 200 liters. The power of electric heating elements is 3 kW. It is necessary to find the time for heating water from 10 degrees to 90 degrees Celsius.

Given:

Wt = 3 kW = 3000 W.

Find: The time it takes for the volume of water in the water heater tank to heat up from 10 to 90 degrees.

Solution

The power consumption of heating elements does not change depending on the temperature of the water in the tank. (We will consider how power changes in heat exchangers in another problem.)

It is necessary to find the power of heating elements, as for an instantaneous water heater. And this power will be enough to heat water in 1 hour.

If it is known that with a heating element power of 18.6 kW, the tank will heat water in 1 hour, then it is not difficult to calculate the time with a heating element power of 3 kW.

Answer: The time for heating water from 10 to 90 degrees with a capacity of 200 liters will be 6 hours 12 minutes.

Task 3. Indirect heating boiler heating time

Let's take an example of an indirect heating boiler: Buderus Logalux SU200

Rated power: 31.5 kW. It is not clear for what reasons this was found. But look at the table below.

Volume 200 liters

The snake is made from steel pipe DN25. Inner diameter 25 mm. Outer 32 mm.

Hydraulic losses in the snake pipe indicate 190 mbar at a flow rate of 2 m3/hour. Which corresponds to 4.6.

Of course, this resistance is high for water and new pipe. Most likely, there were risks associated with pipeline overgrowth, high-viscosity coolant and resistance at connections. It is better to indicate obviously large losses so that someone does not miscalculate.

Heat exchange area 0.9 m2.

Fits 6 liters of water in a snake pipe.

The length of this snake pipe is approximately 12 meters.

Warm-up time is written as 25 minutes. It is not clear how this was calculated. Let's look at the table.

BKN snake power table

Consider the table for determining the power of the snake

Consider the SU200 snake heat dissipation power of 32.8 kW

At the same time, the flow rate in the DHW circuit is 805 l/hour. Flows in 10 degrees comes out 45 degrees

Another variant

Consider the SU200 snake heat dissipation power of 27.5 kW

A coolant with a temperature of 80 degrees flows into the snake at a flow rate of 2 m3/hour.

At the same time, the flow rate in the DHW circuit is 475 l/hour. Flows in 10 degrees comes out 60 degrees

Other characteristics

Unfortunately, I will not provide you with a calculation of the heating time for an indirect heating boiler. Because this is not one formula. There are many intertwined meanings here: Starting from the heat transfer coefficient formulas, correction factors for different heat exchangers (since water convection also introduces its own deviations), and this ends with an iteration of calculations based on changed temperatures over time. Here, most likely in the future I will make a calculation calculator.

You will have to be content with what the manufacturer of the BKN (Indirect Heating Boiler) tells us.

And the manufacturer tells us the following:

That the water will be ready in 25 minutes. Provided that the flow into the snake will be 80 degrees with a flow rate of 2 m3/hour. The power of the boiler producing heated coolant should not be lower than 31.5 kW. Ready-to-drink water is considered to be 45-60 degrees. 45 degrees wash in the shower. 60 is very hot water, for example for washing dishes.

Task 4. How much hot water does it take to take a 30-minute shower?

Let's calculate for example with electric water heater. Since the electric heating element has a constant output of thermal energy. The power of the heating elements is 3 kW.

Given:

Cold water 10 degrees

Minimum tap temperature 45 degrees

The maximum temperature of water heating in the tank is 80 degrees

Comfortable flow rate of flowing water from the tap is 0.25 l/sec.

Solution

First, let's find the power that will provide this water flow

Answer: 0.45 m3 = 450 liters of water will be needed to wash off the accumulated hot water. Provided that the heating elements do not heat the water at the time of hot water consumption.

It may seem to many that there is no accounting for the entry of cold water into the tank. How to calculate the loss of thermal energy when water temperature of 10 degrees enters water of 80 degrees. There will obviously be a loss of thermal energy.

This is proven as follows:

Energy spent on heating the tank from 10 to 80:

That is, a tank with a volume of 450 liters and a temperature of 80 degrees already contains 36 kW of thermal energy.

From this tank we take energy: 450 liters of water with a temperature of 45 degrees (through the tap). Thermal energy of water with a volume of 450 liters at a temperature of 45 degrees = 18 kW.

This is proven by the law of conservation of energy. Initially, there was 36 kW of energy in the tank, they took 18 kW, leaving 18 kW. This 18 kW of energy contains water at a temperature of 45 degrees. That is, 70 degrees divided in half gives 35 degrees. 35 degrees + 10 degrees cold water we get a temperature of 45 degrees.

The main thing here is to understand what the law of conservation of energy is. This energy from the tank cannot escape to no one knows where! We know that 18 kW came out of the tap, and there was initially 36 kW in the tank. Taking 18 kW from the tank, we will lower the temperature in the tank to 45 degrees (to the average temperature (80+10)/2=45).

Let's now try to find the volume of the tank when the boiler is heated to 90 degrees.

Used energy consumption of hot water at the outlet of the tap 18317 W

Answer: Tank volume 350 liters. An increase of just 10 degrees reduced the tank volume by 100 liters.

This may seem unrealistic to many. This can be explained as follows: 100/450 = 0.22 is not that much. Stored temperature difference (80-45)

Let's prove that this is a valid formula in another way:

Of course this is a rough theoretical calculation! In the theoretical calculation, we take into account that the temperature in the tank between the upper and lower layers is instantly mixed. If we take into account the fact that the water is hotter at the top and colder at the bottom, then the volume of the tank can be reduced by the temperature difference. It is not for nothing that vertical tanks are considered more efficient in storing thermal energy. Since the greater the height of the tank, the higher the temperature difference between the top and bottom layers. When hot water is consumed quickly, this temperature difference is higher. When there is no water flow, very slowly the temperature in the tank becomes uniform.

We will simply lower 45 degrees to 10 degrees lower. For place 45 it will be 35 degrees.

Answer: Due to the temperature shift, we reduced the volume of the tank by another 0.35-0.286 = 64 liters.

We calculated on the condition that at the time of hot water consumption the heating elements were not working and did not heat the water.

Let's now calculate under the condition that the tank begins to heat the water at the moment of hot water consumption.

Let's add another power of 3 kW.

In 30 minutes of operation we will get half the power of 1.5 kW.

Then you need to subtract this power.

Answer: The tank volume will be 410 liters.

Task 5. Calculation of additional power for hot water supply

Consider a private house with an area of ​​200 m2. The maximum power consumption for heating the house is 15 kW.

4 people live in the house.

Find: Additional power for domestic hot water

That is, we need to find the boiler power taking into account: House heating power + hot water heating.

For this purpose it is better to use scheme No. 4:

Solution

It is necessary to find how many liters of hot water a person consumes per day:

SNiP 2.04.01-85* states that, according to statistics, 300 liters per day are consumed per person. Of these, 120 liters are for hot water at a temperature of 60 degrees. These city statistics are mixed with people who are not used to using so much water per day. I can offer my consumption statistics: If you like to take hot baths every day, you can spend 300-500 liters of hot water per day for just one person.

Volume of water per day for 4 people:

That is, to the heating power of a house of 15 kW, you need to add 930 W = 15930 W.

But if we take into account the fact that at night (from 23:00 to 7:00) you do not consume hot water, you get 16 hours when you consume hot water:

Answer: Boiler power = 15 kW + 1.4 kW for hot water supply. = 16.4 kW.

But in this calculation there is a risk that at the moment of high consumption of hot water at certain hours you will stop heating the house for a long time.

If you want to have a good flow of hot water for a private home, then choose a BKN of at least 30 kW. This will allow you to have an unlimited flow rate of 0.22 l/sec. with a temperature of at least 45 degrees. The boiler power should not be less than 30 kW.

In general, the objectives of this article were focused on energy conservation. We did not consider what was happening at a particular moment, but took a different route to calculate. We followed the undisputed method of energy conservation. The energy expended at the outlet of the tap will then be equal to the energy coming from the boiler equipment. Knowing the power in two different places, you can find the time spent.

Once we discussed the calculation of hot water supply on the forum: http://santeh-baza.ru/viewtopic.php?f=7&t=78

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A series of video tutorials on a private home
Part 1. Where to drill a well?
Part 2. Construction of a water well
Part 3. Laying a pipeline from the well to the house
Part 4. Automatic water supply
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Self-priming pump calculation
Calculation of diameters from central water supply
Water supply pumping station
How to choose a pump for a well?
Setting up the pressure switch
Pressure switch electrical diagram
Operating principle of a hydraulic accumulator
Sewage slope per 1 meter SNIP
Heating schemes
Hydraulic calculation of a two-pipe heating system
Hydraulic calculation of a two-pipe associated heating system Tichelman loop
Hydraulic calculation of a single-pipe heating system
Hydraulic calculation of radial distribution of a heating system
Scheme with a heat pump and solid fuel boiler - operating logic
Three-way valve from valtec + thermal head with remote sensor
Why the heating radiator in an apartment building does not heat well
How to connect a boiler to a boiler? Connection options and diagrams
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Calculations of hot water supply, BKN. We find the volume, power of the snake, warm-up time, etc.
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Radiator section
Published: 05.12.2010 | |

Throughout 2004, our organization received applications for the development of technical proposals for boiler houses for heat supply to residential and public buildings, in which the loads on hot water supply were very different (to a lesser extent) from those previously requested for identical consumers. This was the reason for analyzing the methods for determining the loads on hot water supply (DHW), which are given in the current SNiPs, and possible errors arising when they are used in practice.
E.O. SIBIRKO

Currently, the procedure for determining heat loads on hot water supply is regulated normative document SNiP 2.04.01–85* “Internal water supply and sewerage of buildings.”

The methodology for determining the estimated flow rates of hot water (maximum second, maximum hourly and average hourly) and heat flows (heat power) per hour at average and maximum water consumption in accordance with section 3 of SNiP 2.04.01–85* is based on the calculation of the corresponding costs through water-folding devices (or groups of similar devices with subsequent averaging) and determining the probability of their simultaneous use.

All service tables with data on various specific consumption rates, etc., given in SNiP, are used only for calculating the flow rate through individual devices and the probability of their operation. They are not applicable for determining costs based on the number of consumers, by multiplying the number of consumers by specific consumption! This is precisely the main mistake made by many calculators when determining the heat load on the hot water supply.

The presentation of the calculation methodology in section 3 of SNiP 2.04.01–85* is not simple. Introduction of numerous superscript and subscript Latin indices (derived from the corresponding terms in English language) makes it even more difficult to understand the meaning of the calculation. It is not entirely clear why this was done in the Russian SNiP - after all, not everyone speaks English and easily associates the index “ h"(from English hot- hot), index " c"(from English cold- cold) and " tot"(from English total- result) with corresponding Russian concepts.

To illustrate the standard error encountered in calculations of heat and fuel needs, I will give a simple example. Need to determine DHW load for a 45-apartment residential building with a population of 114 people. The water temperature in the DHW supply pipeline is 55°C, the cold water temperature is winter period-5°С. For clarity, let’s assume that each apartment has two similar water points (sink in the kitchen and washbasin in the bathroom).

Option I of calculation is incorrect (we have repeatedly encountered this method of calculation):

According to the table “Rates of water consumption by consumers” of the mandatory Appendix 3 of SNiP 2.04.01–85*, we determine for “Apartment-type residential buildings: with bathtubs from 1500 to 1700 mm long, equipped with showers” ​​the hot water consumption per inhabitant at the hour of greatest water consumption is equal to q hhr, u = 10 l/h. Then everything seems to be quite simple. The total consumption of hot water per house at the hour of greatest water consumption based on the number of inhabitants of 114 people: 10. 114 = 1140 l/h.

Then, the heat consumption per hour of greatest water consumption will be equal to:

Where U- number of residents in the house; g - density of water, 1 kg/l; With- heat capacity of water, 1 kcal/(kg °C); t h - hot water temperature, 55°C; t c - cold water temperature, 5°C.

The boiler room, actually built on the basis of this calculation, clearly could not cope with the load of hot water supply at the moments of peak hot water supply, as evidenced by numerous complaints from the residents of this house. Where is the mistake here? It lies in the fact that if you carefully read section 3 of SNiP 2.04.01–85*, it turns out that the indicator q hhr, u, given in Appendix 3, is used in the calculation method only to determine the probability of operation of sanitary fixtures, and the maximum hourly flow of hot water is determined completely differently.

Calculation option II - in strict accordance with the SNiP methodology:

1. Determine the probability of the device operating.

,

Where q hhr,u = 10 l - according to Appendix 3 for this type of water consumer; U= 114 people - the number of residents in the house; q h0 = 0.2 l/s - in accordance with clause 3.2 for residential and public buildings, it is allowed to take this value in the absence technical characteristics devices; N- the number of sanitary fixtures with hot water, based on the two water points we have adopted in each apartment:

N= 45 . 2 = 90 devices.

Thus we get:

R= (10 x 114)/(0.2 x 90 x 3600) = 0.017.

2. Now let’s determine the probability of using sanitary appliances (the ability of the appliance to supply normalized hourly water flow) during the estimated hour:

,
Where P- the probability of the device action determined in the previous paragraph, - P= 0,017; q h0 = 0.2 l/s - second water flow rate related to one device (also already used in the previous paragraph); q h0,hr - hourly water consumption by the device, in accordance with clause 3.6, in the absence of technical characteristics of specific devices, it is allowed to take q h0,hr = 200 l/h, then:

.

3. Since P h is less than 0.1, we further use the table. 2 of Appendix 4, according to which we determine:

at .

4. Now we can determine the maximum hourly hot water flow:

.

5. And finally, we determine the maximum thermal load DHW (heat flow per period maximum water consumption during the hour of maximum consumption):

,

Where Q ht- heat losses.

Let's take into account heat losses, taking them as 5% of the design load.

.

We got a result more than twice the result of the first calculation! As practical experience shows, this result is much closer to the real needs for hot water for a 45-apartment residential building.

You can give for comparison the result of the calculation using the old method, which is given in most reference literature.

Option III. Calculation using the old method. Maximum hourly heat consumption for hot water supply needs for residential buildings, hotels and hospitals general type by the number of consumers (in accordance with SNiP IIG.8–62) was determined as follows:

,

Where k h - coefficient of hourly unevenness of hot water consumption, taken, for example, according to table. 1.14 reference book “Adjustment and operation of water heating networks” (see Table 1); n 1 - estimated number of consumers; b - the rate of hot water consumption per consumer, adopted according to the relevant tables of SNiPa IIG.8–62 and for apartment-type residential buildings equipped with bathrooms from 1500 to 1700 mm in length, is 110–130 l/day; 65 - hot water temperature, °C; t x - cold water temperature, °C, we accept t x = 5°C.

Thus, the maximum hourly heat consumption for hot water supply will be equal to:

.

It is easy to see that this result almost coincides with the result obtained using the current method.

Application of the hot water consumption rate per inhabitant per hour of greatest water consumption (for example, for “Apartment-type residential buildings with bathtubs from 1500 to 1700 mm long” q hhr == 10 l/h), given in the mandatory Appendix 3 SNiP 2.04.01–85* “Internal water supply and sewerage of buildings”, is illegal for determining heat consumption for DHW needs by multiplying it by the number of inhabitants and the difference in temperature (enthalpy) of hot and cold water. This conclusion is confirmed both by the given calculation example and by a direct indication of this in the educational literature. For example, in the textbook for universities “Heat supply”, ed. A.A. Ionin (M.: Stroyizdat, 1982) on page 14 we read: “...Maximum hourly water consumption G h. max cannot be mixed with the water consumption given in the standards at the hour of greatest water consumption G i.ch. The latter, as a certain limit, is used to determine the probability of operation of water-folding devices and becomes equal to G h. max only with an infinitely large number of water taps.” Calculation using the old method gives a much more accurate result, provided that daily hot water consumption rates are used at the lower limit of the ranges given in the corresponding tables of the old SNiP than the “simplified” calculation that many calculators perform using current SNiP.
The data from the table in Appendix 3SNiP 2.04.01–85* must be used specifically to calculate the probability of operation of water-folding devices, as required by the methodology outlined in Section 3 of this SNiP, and then determine bhr and calculate the heat consumption for the needs of hot water supply. In accordance with the note in paragraph 3.8 of SNiP 2.04.01–85*, for auxiliary buildings of industrial enterprises the value q hr can be determined as the sum of water costs for using a shower and household and drinking needs, taken according to the mandatory Appendix 3 according to the number of water consumers in the most numerous shift.

Hot water supply is usually called the supply of water from elevated temperature via a centralized pipeline and internal engineering structures to private and apartment buildings (including non-residential premises and jointly owned premises). This article is devoted to the calculation of hot water supply.

In this article you will learn:

• How is hot water supply calculated?
• What formula is used to calculate the hot water supply standard?
• How to recalculate hot water supply for general house needs.
• Why control the quality of hot water.

Calculation of hot water supply system

The calculation of a hot water supply system is based on calculating the heat for this type of water supply. The fact is that the average temperature of cold water is 10 °C, but at the outlet this figure is much lower, which creates discomfort for the consumer when using water from a mixer (60 °C). Based on this, when calculating, it is recommended to increase the temperature to 50°C.

The algorithm for calculating the average heat consumption for hot water extraction looks like this:

qm = m* t* c *∆t, kW*h,

where m is water consumption, l/h; t – operating time, h; ∆t – temperature difference; c – specific heat capacity, kW x h/(l x°C).

Calculation of hot water supply standards

The water supply rate (cubic meters per month per person) is determined as follows:

N = Sum (Q x n) x (4.5 + 0.07 + L) x 10, where

Q – water consumption by 1 water folding mechanism for 1 operation; n – number of operations using 1 water folding device for i – 7 days; L – the number of floors in an apartment building or residential building.

Consumption rates and average water temperature per operation

The hot water supply indicator (cubic meters per month per person) is calculated as follows:

Calculation of fees for hot water supply: 2 options

Calculation No. 1 – calculation: a hot water consumption meter is installed in the living room.

If an individual metering device for hot water supply is installed in the apartment, the amount of payment for hot water supply will be calculated according to formula No. 1, as the product of the amount of hot water consumed in the apartment according to indications individual device accounting and tariff for hot water supply established for the region and service provider:

Formula No. 1

P i = V i p x T cr

V i p – volume(quantity) of hot water supply consumed during the billing period in a residential or non-residential premises, determined according to the readings of an individual or general (apartment) meter;

T cr – tariff(price) for hot water supply, established in accordance with the law Russian Federation.

Example of DHW calculation

Based on the meter readings, in January 2017. 4 m3 of hot water was consumed.

The cost of 1 m3 of hot water in this region, taking into account the services of an intermediary, is 90 rubles. 00 kop.

Having such data, you can calculate the hot water supply for this particular case:

4 x 90.00 = 360.00 rub.

Calculation No. 2 – there is no hot water consumption meter installed in the residential premises.

For such cases, formula No. 4 is used, which takes into account data on hot water consumption rates in the region, the number of people living in the apartment and the cost of hot water supply, taking into account the region and supplier.

Formula No. 4

P i = n i x N j x T cr

• the number of citizens permanently and/or temporarily residing in the apartment;
• the standard established for hot water supply for the region;
• tariff set for hot water supply for the region and service provider.

Example of DHW calculation

If we take as a basis that three people live in a room, the rate of hot water consumption in this region is 3.5 m 3 / person, and the tariff for hot water supply is 90 rubles. 00 kop. per 1 m 3, then you can calculate the amount of payment for the use of hot water in a given living space as follows:

3 x 3.5 x 90.00 = 945.00 rubles.

Calculation of hot water supply for general house needs

May 06, 2011 The Government of the Russian Federation signed Resolution No. 354 on a new procedure for calculating the amount of payment for utility services. According to this document, apartment residents must pay not only for the hot water they consume at home, but also for the hot water supply that serves the general needs of the building. These changes caused dissatisfaction among citizens, primarily because it was unclear what kind of excess water we were talking about and what such significant volumes of it were being spent on.

Below is a calculation of payment for hot water supply for general house purposes.

• Calculation No. 1 – calculation of domestic hot water supply for a house that does not have a hot water consumption meter installed.

The calculation of the amount to pay for hot water consumed for general house purposes occurs according to formulas No. 10, 15, which allow you to determine the volume of hot water consumed and the amount of the required payment, respectively.

Formula No. 10

P i one = V i one x T cr

• V i od– the amount of hot water that was spent for general house purposes in an apartment building and is accounted for in residential or non-residential premises during the billing period;
• T cr– the cost of hot water supply according to the laws of the Russian Federation.

Formula No. 15

V i single 5 = N single x S oi x (S i / S rev)

• N one– the rate of consumption of hot water supplied during the billing period and spent for general house purposes in an apartment building;
• S i– the total area of ​​residential and non-residential premises in an apartment building;
• S about– the total area of ​​all residential and non-residential premises in an apartment building;
• S oi– the total area of ​​common premises in an apartment building.

Sample calculations

The rate of hot water consumption for general household purposes in the region is 0.3 m 3 per 1 m 2. The total area of ​​premises under common house management is 400 m2. The total area of ​​all residential premises of a given apartment building equal to 4,000 m 2. The total area of ​​one apartment is 45 m2. In this region, the payment for hot water is 90 rubles. 00 kop. for 1 m 3. Using this data, we obtain the following calculations:

0.3 x 400 x 45 / 4000 = 1.35 cubic meters 1.35 x 90 = 121.50 rubles

• Calculation No. 2 - calculation of the domestic hot water supply of a house on which a hot water consumption meter is installed

To calculate payment DHW consumption formulas No. 10, 12 are used, which allow you to determine the volume of hot water and the amount of payment, respectively.

Formula No. 12

Sample calculations

The amount of hot water that was consumed according to the general house meter is 2,000 m3. Amount of hot water consumed in all residential premises according to indications individual meters, equals 1,200 m 3. The amount of hot water consumed in those apartments where there are no individual meters is 500 m3. The total area of ​​the apartments in the house is 4,000 m2. The area of ​​one apartment is 45 m2.

The cost of 1 m 3 of hot water in the region under consideration, taking into account the interests of the service provider, is 90 rubles. 00 kop.

Based on the above data, the calculation of payment for hot water supply for general house purposes is as follows:

(2,000 - 1,200 - 500) x 45 / 4000 = 3.375 cubic meters 3.375 x 90.00 = 303.75 rubles

Summarizing the presented examples of calculations, it should be said that in the absence of a collective meter, the volume of hot water for common house needs will be determined by the area of ​​​​commonly owned premises and the tariff for hot water supply.

It is important to know that if excess cubic meters of hot water are detected, a common house meter will allow you to understand the reasons for this phenomenon. If there is no such meter, then it is not possible to find the cause of the excess and influence the amount of payment for general household hot water consumption.

Calculation of hot water supply load

Calculation of the hot water supply load is required when the following occurs:

• reduction of design heat loads;
• reduction of heating costs;
• coordination of changes in the composition of heat-consuming installations (change in the number heating devices or disassembly ventilation system). This happens if the type of ventilation in the room is changed or a thermal curtain is installed;
• the need to confirm that the new heat load and heat energy consumption are within the design standards;
• planning own system heating;
• planning individual node heat supply;
• if it is necessary to correctly distribute the heat load between subsubscribers;
• connection of new objects (single and/or complex structures) to the common heating main;
• signing a new agreement with the heat supplier;
• the need to specify thermal loads in non-residential premises for individual institutions;
• repayment by organizations of the cost of services by settlement method (in cases where it is impossible to install a meter);
• unreasonable increase in heat energy consumption by the supplier or management company.

As for the rights of consumers in the field of calculating thermal energy for hot water supply, they are fixed:

• in all standard contracts concluded regarding the supply of heat and energy resources;
• in the order of the Ministry of Regional Development of the Russian Federation dated December 28, 2009. No. 610 “On approval of the rules for establishing and changing (revising) heat loads.”

According to this document, the re-examination of contractual indicators should be preceded by the creation of a technical report, which will reflect the calculation of heat loads, and also provide arguments for the need to adjust or reduce the heat load on a specific facility.

In addition, the order of the Ministry of Regional Development of the Russian Federation dated December 28, 2009. No. 610 allows adjustments to be made to the calculation of heat for hot water supply, heating and ventilation in the following cases:

• when carrying out major repairs;
• when restoring internal engineering structures aimed at reducing waste of energy resources;
• when increasing the thermal insulation of a specific object;
• when carrying out other procedures aimed at preserving energy resources.

Before starting to review the thermal loads for existing buildings and connections to common system new objects required:

• collect all available information about the object;
• carry out an audit of the facility's energy system;
• calculate heat loads for hot water supply, heating and ventilation based on the test results;
• write a technical report;
• discuss the report with the heat and power supply company;
• make adjustments to the existing one or sign a new agreement with the energy supply company.

Hydraulic calculation of hot water supply

The main goal hydraulic calculation hot water supply is the calculation of the size (in particular, diameter) of the pipes through which water is supplied, and the costs of pressure. The starting value for such calculations is considered to be the second flow rate, which takes into account the value of the residual circulation:

qh, сir = qh (1 + kсir), l/s,

V in this case kсir - residual circulation index.

To calculate this parameter, you need to divide the second flow rate by the circulation flow inside the hot water supply system. The formula will look like this:

kсir = f(qh/qсir).

In this situation, the conditions are such that kсir ≠ 0 only in the very first parts of the pipeline, despite the fact that qh/qсir is greater than two. In all other cases, kсir will be equal to 0. An important point is that the hydraulic calculation is drawn up before calculating the circulation. This fact implies that the specialist is forced to put forward a hypothesis about the parameters of the qh/qсir ratio (for residential buildings, usually qh/qсir is greater than 2.0) and give reasons for it.

Calculation of the size of pressure costs in water risers, united by a ring jumper into sectional units, is carried out on the basis of calculated water costs with an index of 0.7. For the calculated flow rate in ring sections, it is customary to take as the lowest threshold the highest second flow rate for one of the devices that is subject to maintenance.

As for the speed of water movement in the hot water supply pipeline, it should not exceed three meters per second. But it has been proven that water speeds exceeding one and a half meters per second cause noise.

In order to calculate the diameter of the riser when the resistance does not match, it is customary to take the calculated flow rate and pressure at the very base of the riser as a basis. If the resistance indicators are identical, the diameter of the outer riser is taken as a single value.

To carry out competent hydraulic calculations of any kind, it is necessary to have an understanding of the basic laws of hydrodynamics (among other things, the Darcy-Weisbach equation). But you need to be prepared that each area will impose its own specifics on the implementation of hydraulic calculations (for example, calculations in the field of hot water supply are very typical, which eliminates the need to calculate pressure costs separately).

There is an algorithm for calculating pressure losses in sections of the hot water supply system:

Н = i×l(1 + kl), mm,

where i is the specific linear pressure loss, mm/m; l is the length of the section; kl is an index that takes into account pressure losses in local resistances.

Indicators i are taken from the corresponding reference books.

Do not forget that there may be cases when hard water from the pipeline is heated to provide hot water supply. This situation is fraught with the appearance of growths inside the pipes (so-called hardness salts). In this situation, a nomogram is used to calculate the index i.

• Available and required pressures in DHW systems in water withdrawal mode

The pressure guaranteed at the input and used, if necessary, to supply water for hot water supply purposes is called available. Another type of pressure - required, is characterized by the fact that it serves to pass hydraulic resistance when supplying water to the device that is as distant as possible (in distance and in height).

If we take as an example closed system hot water supply, then the available pressure will be the pressure of the cold water supply at the junction with the hot pipeline. And to calculate the required pressure, the following formula is used:

Ntreb = Npod + Nsch + Nvn + Ng + Nsv,

where Npod is the pressure loss in the supply pipelines in water withdrawal mode; Nsch – pressure loss in the water meter (water meter); NVP – pressure loss in the water heater; Ng – the difference between the geodetic indicators of the highest possible device and the point of connection of the hot water supply system with the cold water supply; NSV – free pressure on the device (“to the spout”).

For open system supply of heat resources, which involves disassembling directly from the heating main, the available pressure will be in the return water supply of the heating main at the connection point of the hot water supply system. The calculation of the required pressure (in the absence of a water heater) will be done as follows:

Ntreb = Npod + Nsch + Ng + Nsv,

where Ng is determined from the specific location of connection to the heating main. In hot water supply systems operating on the principle of gravity flow under the influence of the water column in storage vessels, the available pressure is taken directly from the geodetic difference between the water level in such a vessel and the highest device located. The calculation of the required pressure for this situation looks like this:

Ntreb = Npod + Nsv

Recalculation and calculation of hot water supply

Article 542 of the Civil Code of the Russian Federation establishes that the quality of the provided energy resources must meet the criteria established by the law of the Russian Federation, as well as the clauses of the agreement on the supply of energy resources. Article 538 of the Civil Code of the Russian Federation prescribes the application of the above rules to relations arising during the supply of energy resources, since the law does not provide for any other procedure.

The temperature of hot water in water collection points is regulated by clause 2.4 of SanPiN 2.1.4.2496-09 “Hygienic requirements for ensuring the safety of hot water supply systems”, approved by the Resolution of the Chief State Sanitary Doctor of the Russian Federation dated April 7, 2009. No. 20. According to this document, t at the outlet should not go beyond 60 - 75 °C. The requirements of SanPin must be strictly observed by those legal entities whose occupation is related to the implementation and establishment of the hot water supply line.

Subparagraph “B” of paragraph 17 of the Rules for concluding contracts for the supply of energy resources speaks of the importance in this area of ​​such an indicator as the quality of the resources provided, which should ensure the maintenance of common property at the proper level. Utility services must be provided to citizens in full accordance with the Rules for the provision of utilities and connection conditions apartment buildings and common networks of engineering and technical support connecting them to centralized networks engineering and technical support (clause 20 of the Rules for concluding contracts for the supply of energy resources).

According to clause 5 of Appendix 1 to the Rules for the provision of public services, the quality of public services in the field of hot water supply must meet the following criteria: guarantee compliance temperature regime at the water collection point in accordance with the law of the Russian Federation on technical regulation and the provisions of SanPin.

The responsibilities of the repair and construction organization, which is responsible for the supply of water, include ensuring its quality and desired temperature(in the range from 60 to 75 °C), although the law of the Russian Federation does not give strict regulations on this issue. The supplier company is responsible for ensuring that the coolant reaches citizens in proper quality. If the temperature of the water is less than the lower limit established by the standards (Resolution of the AS ZSO dated October 12, 2015 No. F04-24751/2015 in case No. A45-19993/2014), citizens have the right to file a claim in court, which will oblige the defendant (company - energy supplier) to correct the violations.

Clause 5 of Appendix 1 to the Rules for the Provision of Public Utilities allows for deviations from the temperature limits established by law. Thus, the deviation from the accepted temperature at night from 00 h. 00 min. until 05:00 may be 5°C; in the afternoon from 05:00 until 00 h. 00 min. - 3 °C. Despite the existence of such reservations, such a provision is not considered the norm. Decision of the Supreme Court of the Russian Federation of May 31, 2013. No. AKPI13-394 states that such deviations are indicators of the provision of services of inadequate quality.

In order for the hot water temperature at the water collection points to be 60 °C, at the entrance to the house it must be an order of magnitude higher. However, as already mentioned, there are no legislative requirements regarding this particular indicator, therefore, in the event of going to court, we can only talk about the fact that the repair and construction company must ensure that the temperature of the water entering the house is not less than 60°C.

When can the manager of an apartment building apply for a recalculation of the cost of hot water?

Paragraph 2 of Article 542 of the Civil Code of the Russian Federation gives citizens the right to refuse to pay for energy resources of inappropriate quality. But the supplier company is also allowed to demand compensation for energy losses from citizens in this case.

There are also legislative requirements regarding changes in the procedure for payment for consumed energy resources if they were not of adequate quality or were supplied intermittently beyond the permissible period (subparagraph “d” of paragraph 22 of the Rules for concluding resource supply contracts). The rules for the provision of utility services regulate the procedure for recalculating payments.

The current legislation of the Russian Federation recognizes the unconditional advantage of a system for monitoring consumed resources through the installation of meters on the border area between the area of ​​​​responsibility of the supplier company and the property of citizens. If a meter is installed at home and there are no complaints about its operation, then the indicators of this device can be considered evidence of the supply of insufficient quality water. The repair and construction organization must provide evidence refuting this information, otherwise the payment for expended resources must be recalculated (resolution of the AS UO dated January 11, 2017 No. F09-10932/16 in case No. A60-59444/2015).

This provision is also confirmed by subparagraph “B” of paragraph 111 of the Rules for the provision of public utility services, which determines the date and time of the start of the provision of low-quality services in accordance with the date and time recorded by the devices intended for this (for example, OPU, IPU, etc.). Moreover, the presence of a meter and its readings eliminates the procedure for confirming the provision of services of inadequate quality in accordance with the requirements of Section X of the Rules for the Provision of Public Utilities (Resolution of AS PO dated January 16, 2017 No. F06-15316/2016 in case No. A12-4577/2016).

In cases where appropriate measuring instruments is not installed on the building, to confirm the fact of provision of low-quality services, you will need to collect a number of documents, as well as follow the procedure set out in section X of the Rules for the provision of utility services:

• record the citizen’s signal to the emergency dispatch service (paragraphs 105, 106, subparagraph “b” of paragraph 111);
• agree with the citizen on the timing of checking the information provided about the violation, notify the repair and construction organization that the service it provides will be checked if the supplier does not know the reasons for the violation (clause 108);
• carry out an inspection upon a signal from the consumer; all data obtained during the inspection must be recorded in writing in a specific form (clause 109). The inspection is intended to confirm a violation in the quality of the service provided (the act of measuring the temperature at the point of analysis in a residential premises) and to clarify its reasons (the act of measuring the temperature at the entrance to the house).

Summary tables and calculations compiled by the Criminal Code unilaterally, in the absence of reports on the quality of public services, will not be accepted by the court as evidence (Resolution of the Central District Court of October 20, 2016 No. F10-2735/2016 in case No. A14-6593/2015).

Please note that regulations do not link the establishment of the fact of delivery of a low-quality resource with the fact of recalculation by the utility service provider to the owners of premises of payment for low-quality service (Resolution of the AS ZSO dated September 19, 2016 No. F04-3939/2016 in case No. A03-12727/2015), although such a condition may be included in resource supply agreement based on the agreement of the parties, and then must be respected.

How hot water supply is recalculated

Subparagraph “D” of paragraph 22 of the Rules for concluding contracts for the supply of resources says that the recalculation of the cost of poorly provided services occurs in accordance with the Rules for the provision of public services. This is confirmed by the Decision of the Supreme Court of the Russian Federation No. AKPI13-394, which states that if there are no additional documents that record the procedure for recalculation, a representative of citizens living in an apartment building may qualify for a reduction in fees for the provision of services with a violation of their quality in accordance with the requirements of SanPin. Moreover, the recalculation should be carried out in the same way as the recalculation for direct consumers (resolution of the Central Election Commission of February 29, 2016 No. F10-5264/2015 in case No. A09-1717/2015).

Clause 101 of the Rules for the Provision of Utility Services prescribes that the fee for hot water supply for the billing period should be reduced by the total amount of payment for the entire period of provision of low-quality services in the cases specified in the documents (see Appendices 1 and 2 of the Rules for the provision of utility services).

The total cost of services with poor quality can be determined by multiplying the cost of the service for the entire billing period (Appendix 2 of the Rules for the Provision of Public Utilities) by the ratio of the duration of provision poor quality service within this period to the total duration of utility service provision for the billing period.

To calculate utility bills for hot water supply, the following values ​​are used:

Pi – the amount of payment for the provided utility service for the billing period (according to Appendix 2 to the Rules for the provision of utility services);

Δ – the total amount of payment for all days of provision of poor-quality services (or the amount by which payment should be reduced for the billing period);

t – duration of provision of low-quality services within one billing period.

The duration of the billing period is determined by the entire duration of the supply of energy resources in accordance with the principles of constancy and non-stop of this process. Based on the previously described rules for calculating payment (paragraph 2 of clause 101 of the Rules for the provision of utility services), you can create the following formula (assuming that the month consists of 31 days):

Δ = Pi x t / 31 days.

The reduction in payment for violation of temperature conditions occurs according to the following principle: payment is reduced by 0.1% for every 3°C different from the norm (Appendix 2 to the Rules for the Provision of Public Utilities) and for each hour in total throughout the entire billing period in accordance with Section IX of the Rules for the Provision of Public Utilities. If the hot water temperature drops below 40 °C, then each hour of service provision in a similar manner for the entire billing period is paid at the rate of payment for the use of cold water.

Calculations are based on the following parameters:

• the amount of payment for the corresponding service for the billing period within which failures in the organization of hot water supply were recorded (Pi1);
• the amount by which the service fee is reduced (in %) varies depending on fluctuations in water temperature: - 0.1% for every 3 °C;
• duration of service provision with quality violations in the aggregate for the entire billing period, expressed in hours (t1) and taking into account the rules of Section IX of the already mentioned rules.

Taking as a basis all the information indicated above, the calculation of the amount of fee reduction is carried out according to the following algorithm:

Δ = Рi1 x % x t1

The provision of paragraph 5 of Appendix 1 to the Rules for the Provision of Public Utilities allows this formula to be applied, despite the requirements of paragraph 101 of the same Rules.

Unfortunately, the previously given definitions contain imperfections that cause numerous disputes and even lead to the filing of lawsuits. Basically, the misunderstanding is associated with two quantities, the first of which (Pi1) helps determine the size of the payment reduction. According to paragraph 5 of the app. 1 to the Rules for the Provision of Public Utilities, this payment is characterized as payment for the billing period within which the payments were made temperature disturbances. However, it is worth considering in more detail the concept of a billing period and outlining its scope.

Clause 37 of the Rules for the Provision of Public Utilities speaks of the billing period as a period of time equal to one calendar month. This is confirmed by calculations in the Letter of the Ministry of Regional Development of the Russian Federation dated June 4, 2007. No. 10611-UT/07. It is known that in private clarifications the Ministry of Construction is also of the opinion that the monthly fee should be taken into account in the calculation.

It should be said that the definitions from the current Rules for the provision of public utility services coincide in meaning with the wording that has already ceased to have meaning in the form of activity criteria in the part under consideration (clause 5 of Appendix 1).

Clause 101 of the Rules for the provision of utility services states that payment for services for a billing period equal to a month is subject to reduction by the total amount of payment for each period of provision of services with violations, equal to one day. Thus, it is necessary to calculate the cost of providing poor-quality service for 1 day.

The decision of the Supreme Court of the Russian Federation No. AKPI13-394 decides that paragraph 5 of Appendix 1 to the Rules for the Provision of Public Utilities fixes such a change in the rules for paying for public services of insufficient quality, in which there is no possibility of not making payments at all for the supplied water with a violation of quality. If we take the value of the payment for the month as the value of parameter Pi1, then even in the case of short-term and non-serious violations, the amount of payment reduction will very quickly approach this indicator, and the citizen will have to be exempt from paying for hot water supply services for the month in question. Based on this thesis, judges often reject the claims of managers apartment buildings who provided calculations of the amount of payment taking into account the amount of payment per month.

Thus, the Resolution of the Supreme Court of the Russian Federation dated October 14, 2016. No. F01-3504/2016 in case No. A39-6742/2014 says that the developed payment system for the period of poor-quality implementation of water supply services, in which the degree of reduction in the amount of payment for hot water supply is considered cumulatively for the billing month, implies the possibility of not paying a wasted low-quality resource, however, this is wrong. If we take a case in which the temperature of water supplied to consumers was below normal by 18°C ​​continuously for 9 days, then according to this calculation system, payment for hot water per month will be 00 rubles. 00 kop. Having studied paragraph 101 of the Rules for the provision of public utility services in more detail, one can understand that the billing period for the provision of services with a violation of quality should be considered 1 day, which is confirmed by the opinion of many representatives of the panel of judges (see decisions of the AS ZSO dated October 25, 2016 No. F04-4511/2016 in the case No. A45-26014/2015, AS UO dated 03/31/2017 No. F09-1379/17 in case No. A60-14516/2016, dated 02/06/2017 No. F09-11636/16 in case No. A71-4808/2015).

However, in some cases, judges take the other side and recognize the legality of calculating the amount of payment with a billing period of one month (see, for example, Resolution of the AS ZSO dated June 15, 2016 No. F04-2184/2016 in case No. A03-21553/2014).

As a possible solution, managers of an apartment building can request from the Ministry of Construction documentary evidence of the objective procedure for calculating the reduction in payments for hot water supply of inadequate quality, which can be used in court as evidence. However, the court has the right not to accept this document as evidence, justifying its position by the fact that the proposed documents do not have the status of normative acts.

In the case when the payment amount for one day is taken as a basis and a meter is installed on the house, it is more correct to carry out calculations based on the actual amount of water consumed per day, which was recorded by the device. If there is no meter, then calculations are carried out using a formula that requires dividing the total volume of resource recorded and delivered to the house by the number of days in the month.

Clause 5 of Appendix 1 to the Rules for the Provision of Public Utilities requires that the payment for hot water be reduced by 0.1% for every 3 °C violation of the norm. The following criteria are also introduced here: deviation from temperature standards by 5°C at night and by 3°C during the day. Thus, the precise interpretation of this regulation implies that the payment for hot water consumed should not be reduced if its temperature at night did not fall above 55 °C and below 57 °C during the day. However, if the temperature continues to fall relative to the already reduced values, then for every subsequent 3°C ​​(i.e. up to 54°C) the payment will be reduced by 0.1% every hour (at 51°C - 0.2%, etc.). d.). This approach also found support among representatives of arbitration (resolutions of the Arbitration Court No. F09-1379/17 of March 31, 2017 in case No. A60-14516/2016, of the Arbitration Court of the Far Eastern District of May 24, 2016 No. F03-976/2016 in case No. A24-1520/ 2015).

But the Decision of the Supreme Court of the Russian Federation No. AKPI13-394 says that the establishment in paragraph 5 of Appendix 1 to the Rules for the Provision of Public Utilities of permissible deviations from the temperature regime prescribed by SanPiN 2.1.4.2496-09, in fact, means making adjustments to sanitary and epidemiological standards, regulating the quality level of hot water, aimed at compliance with anti-epidemic measures. Such a situation conflicts with the already mentioned legislative norms and requires the recognition of this norm as invalid in this context. Thus, we return to the fact that any deviation from the prescribed standards will be equated to violations of the quality of service provision. The discussed criteria continue to apply in matters of the conditions and procedure for changing the amount of payment. Based on this, we can conclude that a percentage of 0.1% reduction in payment for the use of hot water of inadequate quality should be charged for any violation of the temperature regime (starting from 57°C during the day and 55°C at night). In accordance with the documentary base, this approach looks more correct. He also finds support in the judicial system.

Guided by these considerations, managers of apartment buildings must support their position with calculations that promise great benefits, and base their line on the fact that no deviations from temperature standards should be allowed.

There is also a nuance related to whether it is possible to calculate the exact amount of the payment reduction if the deviation from the norm does not coincide with the “step” prescribed in the standards. There is a point of view that recommends calculating the reduction in payment taking into account tenths if the temperature drops by less than 3°C. An example can be given when the water temperature dropped to 55°C during the day. In this case, it is possible to calculate that the percentage of reduction in payment for the cost of the service will be equal to 0.167% (5/3 x 0.1%). However, the question arises about the legality of such calculations. Clause 5 of Appendix 1 to the Rules for the Provision of Public Utilities does not allow us to say that this correct solution. We remember that for every 3°C the payment decreases by 0.1%, this allows us to derive a certain pattern.

This is exactly the method of calculation that is given in Letter of the Ministry of Regional Development of the Russian Federation No. 10611-YUT/07. A Resolution of the AS UO dated October 28, 2016 No. F09-9955/16 in case No. A71-5017/2015 emphasizes that the calculation of the Criminal Code is incorrect, because takes tenths of a degree into account.

Expert opinion

Why control the quality of hot water?

A.N. Sokolova,

tax lawyer

The reality is that direct consumers of hot water supply (ordinary citizens, schools, kindergartens and other organizations) cannot, from a technical point of view, use necessary equipment monitor the quality of hot water, determine its characteristics such as color, turbidity, the amount of iron and other substances contained in the water, etc. Also, not everyone can seek legal advice. All this implies that manufacturers and suppliers of heat and energy resources must approach their responsibilities with full responsibility.

A similar position is manifested in the implementation of strict control over the quality of services provided, in the prompt elimination of identified violations and the implementation correct calculation citizens for the services provided in this case. This result can be achieved if all parties to the process of providing the population and other entities with heat energy direct their efforts to control the quality of the services provided. It is important that organizations responsible for providing energy resources follow the letter of the law when it comes to payment for services and do not insist on payments for cases of quality violations. Their actions must be based on the following regulations:

• clause 2 art. 542 of the Civil Code of the Russian Federation - for organizations involved in the supply of energy resources;
• Rules for the provision of utility services - for management companies.

If you do not adhere to these standards, then it will be very difficult to get supplier companies to take proper measures to eliminate possible violations in the process of supplying energy resources. Violations of the rules for the provision of services in this area and incorrect calculation of the population for the low-quality resources provided do not allow optimizing the situation in this area in many localities.

Example 1. Calculate the hot water supply system for a five-story, two-section residential building. The network was designed based on the building plan given in appendix. 1, 2. The design diagram of the network is shown in Fig. 2.1 (similar to the cold water supply network diagram).

Superheated water from the heating network with parameters tn = 120 °C and tk = 70 °C is used as a coolant.

Data on cold water supply are taken from example 1 given in clause 1.7.

The hot water supply system is centralized with the preparation of hot water in a high-speed water heater with variable output using coolant from the heating network.

The hot water supply network diagram is adopted as a dead-end with lower mains routing (as is the cold water supply network).

Since the consumption of hot water is uneven, the network is adopted with circulation in the main and risers.

Determined estimated costs hot water and heat. Hot water consumption in network sections is determined by formula (2.1). Since the system serves identical consumers, the value P h is found according to formula (2.3).

Here the magnitude and are taken according to adj. 3 [1].

The value is determined by formula (2.7)

The value is taken according to adj. 3 [1].

The maximum hourly consumption of hot water is determined by formula (2.5)

The value is determined according to Table 2, appendix. 4 [1].

The average hourly consumption of hot water is determined by formula (2.8)

, m 3 / h

The maximum hourly heat consumption is determined by formula (2.11)

Rice. 2.1. Design diagram of the hot water supply network

Table 2.3

An example of calculating a hot water supply network in water withdrawal mode.

Settlement area	Length of thread, m	Number of devices, N	Probability of operation of devices, Р t	N*P	α	Consumption of one device, q t 0 l/s	Design flow rate, q t l/s	Diameter, d mm	Speed, V m/s	Specific pressure loss, mm/pm	Pressure loss in the area, mm	Notes
1-2	1,50		0,016	0,016	0,205	0,09	0,09		0,78
2-3	0,55		0,016	0,032	0,241	0,2	0,24		2,08
3-4	0,80		0,016	0,048	0,270	0,2	0,27		2,35
4-5	3,30		0,016	0,048	0,270	0,2	0,27		1,13
5-6	2,80		0,016	0,096	0,338	0,2	0,34		1,42
6-7	2,80		0,016	0,144	0,393	0,2	0,39		1,63
7-8	2,80		0,016	0,192	0,441	0,2	0,44		1,84
8-9	4,00		0,016	0,240	0,485	0,2	0,49		1,17
9-10	10,00		0,016	0,800	0,948	0,2	0,95		1,2
10-water	13,00		0,016	1,920	1,402	0,2	1,40		1,34
water-sch	7,00		0,013	2,106	1,479	0,3	2,22		2,1
input	10,00		0,013	2,106	1,479	0,3	2,22		1,05
11-12	3,30		0,016	0,096	0,338	0,2	0,34		0,91
12-13	2,80		0,016	0,192	0,441	0,2	0,44		1,19
13-14	2,80		0,016	0,288	0,524	0,2	0,52		1,44
14-15	2,80		0,016	0,384	0,598	0,2	0,60		1,65
15-9	4,00		0,016	0,480	0,665	0,2	0,67		1,84

The heating surface of the heating tubes of the water heater is determined by formula (2.13). The calculated temperature difference is determined by formula (2.14). Let's take the coolant parameters t n = 120 °C, t to= 70 °C, parameters of heated water t h=60 C and t c=5 C.

°C

According to adj. 8 [2] accept high-speed water heater N 11 VTI - MosEnergo with a heating surface of one section of 5.89 m. The required number of sections will be determined by formula (2.16)

sections

Section length 2000 mm, outer diameter of the body 219 mm, number of tubes 64.

The calculation of the hot water supply system in water withdrawal mode is carried out in tabular form (Table 2.3).

Pressure losses in sections of the hot water supply network were determined using formula (2.19). Magnitude K l 0.2 was accepted for distribution pipelines and 0.1 for water risers without heated towel rails. (It is accepted to connect heated towel rails to the heating network.)

Total losses the pressure on line 1-input is 21125 mm or 21.1 m. Since the riser St TZ-2 has twice the hydraulic load than the riser St TZ-1, a diameter of 25 mm was adopted for it and the speeds and pressure losses on this riser were calculated. Since the pressure losses in sections 4 - 8 turned out to be greater than in sections 11 - 15, the riser St TZ-1 was taken as the design one.

The required pressure at the entrance to the building for the operation of the hot water supply system is determined by formula (2.20)

Here, the pressure loss in the water heater is determined by formula (2.17)

The calculation of the hot water supply system in circulation mode is carried out in tabular form (Table 2.4). The design diagram of the network is shown in Fig. 2.1.

Table 2.4.

Calculation of hot water supply network in circulation mode

Settlement accounts	Length	Circulation flow, l/s	Diameter, mm	Speed, m/s	Pressure loss, mm	Notes
for 1 linear m.	at school
water-4	13,00	0,28		0,27	6,24
4-3	10,00	0,19		0,24	4,30
3-2	4,00	0,10		0,24	10,00
2-1	11,20	0,10		0,42	45,98
1-2″	11,20	0,10		0,42	45,98
2″-3″	4,00	0,10		0,42	45,98
3″-4″	10,00	0,19		0,45	36,13
4″-input	13,00	0,28		0,35	13,88
					Total: 1340

The circulation flow in the sections was taken according to formula (2.23). The diameters of the circulation pipes in the risers were taken to be the same as the diameters of the distribution pipes; on highways they were accepted one size smaller.

The total head loss due to friction and local resistance in the network was 1340 mm. Here it is necessary to take into account the pressure loss in the water heater when the circulation flow is passed, which are determined by formula (2.17)

M = 7.9 mm = 8 mm

Thus, the pressure loss in the design circulation ring will be

Opportunity identified natural circulation. The natural circulation pressure is determined for a system with lower wiring according to formula (2.25)

13.2 (986.92 - 985.73) + 2(985.73 - 983.24) = 20.69 mm

The pressure loss in the circulation ring (1348 mm) significantly exceeds the natural circulation pressure (20.69 mm), so pump circulation is designed.

The performance of the circulation pump is determined by formula (2.26)

The required pump pressure is determined by formula (2.27)

According to adj. XIII [3] we accept the K50-32-125 (K8/18b) pump with a nominal capacity of 2.5 l/s and a head of 11.4 m. These values ​​​​exceed the calculated ones, therefore it is possible to replace the engine with a speed of 2860 rpm with 1480 rpm min. From formula (7.1) [3] we determine that

l/s; m.

In this case, the power on the pump shaft will become

kW

Here the quantities Q 1 , H 1 , N 1 correspond to the number of revolutions n 1=1480 rpm

3. DESIGN OF THE INTERNAL WATER WATER SYSTEM

The drainage system includes a set of engineering devices inside the building for receiving Wastewater and their discharge outside the building into the street drainage network. It consists of the following main elements:

Wastewater receivers - sanitary fixtures;

Hydraulic valves (siphons);

Branch lines;

Risers with exhaust pipes;

Issues.

A special place is occupied by the yard drainage network, which serves to drain wastewater from buildings into street sewers.